Finding Failures Before They Happen

Typically, forensic engineers are thought of as claim service providers for the insurance industry. Most forensic engineers are called in after failures and catastrophes to help identify possible causes, provide scopes of repair, and identify potential avenues of subrogation.

Forensic engineers can provide another, equally valuable, service to the insurance industry, however. They can help to identify potential signs of failure in structures before disasters occur, which can be beneficial from an underwriting and risk management point of view.

Complete failure of structural elements in buildings, thankfully, does not occur frequently. However, some common causes of building failures can be related to structural members, as well as building envelope, electrical, fire protection, mechanical, HVAC, and plumbing systems. Many structural elements of major buildings are concealed by finish work and, therefore, hidden from view. Due to the threat posed to both human life and property, evaluation of structural elements is best performed by forensic engineers.

Major structural elements that forensic engineers will attempt to inspect often include foundations, floor joists, framing members, columns and beams, and roof framing members. Inspection of these structural elements normally begins with a visual and photographic evaluation that identifies signs of cracking or shifting of building foundations; cracking, shifting, corrosion, or decay of structural and framing members; and signs of previous damage, such as from water intrusion.

Structural Components

Inspection of the envelope of a structure can provide insight into potential failures. The term building envelope refers to all of the elements of a building that protect the interior and structure of a building from the elements, such as roofs, water-shedding elements (e.g., gutters and scuppers), as well as sheathing, insulation, siding, paint, and exterior barrier systems.

The exterior insulation and finish system is an exterior barrier system that has received a great deal of attention in recent years. Proper installation of EIFS is complicated and sensitive to construction details. In many cases, inspection by trained and certified third-party EIFS inspectors can pinpoint potential problems in structures with EIFS before serious damage can occur.

When inspecting the envelope of a building, forensic engineers typically are looking for signs of previous or potential future damage, such as small regions of moisture, mildew, or mold that may have gone unnoticed, caused by potential avenues of water intrusion from failures of sealants or barrier components. Such inspections often involve infrared examination, to detect hot or cold regions, or other methods of detecting previously unnoticed failures.

The mechanical systems inside a building can be another source of risk. Failures in piping and plumbing systems are of major concern, due to the high cost of cleanup and repair. A thorough inspection of these systems can uncover possible signs of failure, including pipe corrosion, water pressure or water hammer issues, potential failure points of plumbing components, and the presence of components that may be under recall. A visual inspection usually is the first method of identifying problems. Methods such as water testing, borescope examination, infrared inspection, also may be used to detect potential failures in plumbing systems.

Heating, ventilating, and air-conditioning systems are additional sources of claims in buildings, particularly in large commercial structures. Inspection of both the HVAC system and any maintenance or repair logs associated with those systems can be extremely valuable in pointing out potential failures and taking steps to prevent those failures.

Boilers, oil heating, and other fuel gas systems in structures are a third element of mechanical systems that should be inspected by trained forensic engineers. Due to the fire potential associated with failure in those systems, and a number of recalls that may affect installed equipment, review of the installation of those systems and their maintenance and repair records can provide valuable data to risk management professionals.

In steam-heated buildings and structures, regular boiler inspections are necessary to ensure continued safety and reliability. Review of maintenance, repair, and testing logs, along with inspection and testing of the steam generation and distribution systems, can provide valuable insight into the condition of those building systems.

Consulting forensic engineers also can be useful in diagnosing potential failures in electrical systems. Factors such as misconfigured systems, poor incoming power quality, or improper installation and maintenance of electrical systems often can be detected by careful inspections. Electrical testing equipment, ground testing equipment, and infrared examination can help pinpoint potential issues in electrical systems that may not be identified by simple visual examinations. Infrared examination is particularly useful in this regard, as it allows engineers to locate possible hot spots in electrical systems while power is applied.

In other situations, such as those involving the installation of scientific, medical, or computer equipment, power quality surveys can ensure that incoming electricity is properly conditioned and adequate for sensitive equipment. These types of surveys can help prevent expensive losses to expensive equipment, for a relatively low cost.

Fire Protection Systems

Many commercial and industrial structures have fire protection systems integrated into the buildings. The performance of these systems is a critical factor in understanding the risks associated with any particular property. Fire protection systems behave like plumbing systems in many respects, but have specific failure modes. For example, wet fire protection systems, in which the piping always is filled with liquid, remain stagnant for long periods of time. In many cases, stagnant water makes the piping more prone to corrosion and failure than plumbing systems.

Similarly, dry-pipe systems, in which the piping is filled with air under pressure until the fire protection system activates, often collect moisture and condensation in low points in the system; again, providing environments in which stagnant water can promote corrosion.

In addition to uncovering areas of potential failure, inspections by trained forensic and fire protection engineers can help identify components under recall, such as the widely publicized recall of millions of Central Sprinkler sprinklers and Poz-Lok piping.

Due to the nature of their work, forensic engineers generally have access to a number of specialized tools to help identify potential failures. The simplest and most widely used of these is the visual inspection, in which documentation by photography and videography are commonly employed. The only drawback to visual inspection is that areas that are concealed cannot be easily inspected with the eye only.

In fact, most other inspection techniques really are methods that allow engineers to visualize areas in new ways. A borescope, for example, enables engineers to inspect the interior of tight spaces. Borescopes come in numerous sizes and shapes, and can allow visual inspection through holes smaller than one millimeter. Fiberscopes are similar in nature, but are equipped with articulating heads. Pipe cameras are small diameter video cameras that can be inserted 100 feet or more into plumbing systems for interior inspection. Many borescopes can be attached to video or photographic devices, creating permanent records of significant findings.

In order for a borescope to be used, a penetration into the interior of a wall or piping system must be created. In many cases, however, walls can be inspected by creating small holes behind trim or other cosmetic elements that can be patched quickly and easily. Often, temporary removal of a fixture or fitting can allow access for inspection of the interior of plumbing systems, and cosmetic drain covers can be removed temporarily to allow access to drain systems.

Infrared Examination

Infrared examination is an excellent method for visualizing small differences in temperature. Infrared testing is based on the principle that all objects emit invisible infrared radiation in rough proportions to their temperatures. Infrared cameras capture this invisible form of radiation, converting it into images that can be viewed on monitors or television screens.

Evaluation of these infrared images then can be used to pinpoint a number of potential failures. Due to the sensitivity of some infrared cameras, areas of poor insulation, pinhole leaks in building envelopes, and areas of anomalous electrical activity can be determined. Furthermore, infrared examination normally is noninvasive and can be conducted in finished regions without causing damage.

Electrical systems also can be inspected by infrared examinations. Flowing electricity generates heat in proportion to the amount of electrical current and the resistance of the wire or connection. Therefore, parts of electrical systems that are thermally hot can be identified easily for further inspection.

Ultrasonic and magnetic inspection of metallic materials is another method that engineers commonly use to locate potential problems with building systems and structures. Ultrasonic examinations can find hidden cracks in structural elements and can be used to determine whether corrosion may be causing gross losses of metal in piping, without requiring access to the pipe interior.

Magnetic particle inspections can identify hairline cracks in critical structural members. For example, many cranes are inspected on a regular basis using magnetic particle inspection to prevent catastrophic failures. This technique can be extended to welded, bolted, and riveted structural members in buildings.

In many situations, a battery of simple and inexpensive water tests can help locate potential problems within plumbing or hydronic HVAC systems. In one test, the amount of dissolved copper in a water sample can help determine whether corrosion is occurring. Electrical testing, using a reference electrode attached between piping components and the ground, also can uncover corrosion problems. Another test which can be performed by nearly any water testing laboratory can determine whether incoming water quality could affect piping systems. In most cases, these water tests can be performed with minimal time and effort.

In many plumbing, fire protection, and sewage removal systems, certain types of bacteria can grow under the right conditions. These bacteria present a major corrosion risk and, in many cases, can perforate piping in the span of just a few years. Forensic engineers often take water or pipe samples and, in conjunction with simple, commercially available test kits, determine the types and relative quantities of microbiological agents present in those systems. Given proper information about the states of those systems, risk managers can make more informed decisions.

Due to their specialized training and equipment, forensic engineers perform an essential service by identifying potential failures. In doing so, they can assist risk managers by providing important data about the possibility, and more importantly, the mitigation of various failures in buildings and structures.

Joe Skagg is a senior metallurgist and material engineer with Schaefer Engineering.

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